Question

980.0 has significant figures?

Answer 1

Answer:

$Let the Manoj's present age be x years.</p><p></p><p>After 12 years,</p><p></p><p>His age = (x + 12)</p><p></p><p>Before 4 years,</p><p></p><p>His age = (x – 4)</p><p></p><p>\begin{gathered}\dashrightarrow\sf x + 12 = 3\Big\{x - 4\Big\} \\\\\\\dashrightarrow\sf x + 12 = 3x - 12\\\\\\\dashrightarrow\sf - 2x = - 12 - 12\\\\\\\dashrightarrow\sf -2x = -24\\\\\\\dashrightarrow\sf x = \cancel\dfrac{-24}{-2}\\\\\\\dashrightarrow{\pmb{\sf{x = 12}}}\end{gathered}⇢x+12=3{x−4}⇢x+12=3x−12⇢−2x=−12−12⇢−2x=−24⇢x=−2−24⇢x=12x=12</p><p></p><p>∴ Present age of Manoj is 12 years.</p><p></p><p>\rule{250px}{.2ex}</p><p></p><p>Let the present age of Sonal and Manoj be 7x and 5x.</p><p></p><p>Ten years hence,</p><p></p><p>Sonal's age = (7x + 10)</p><p></p><p>Manoj's age = (5x + 10)</p><p></p><p>\begin{gathered}\dashrightarrow\sf 7x + 10 + 5x + 10 = 9x + 7x\\\\\\\dashrightarrow\sf 9x – 5x = 20\\\\\\\dashrightarrow\sf 4x = 20\\\\\\\dashrightarrow\sf x = \cancel\dfrac{20}{4}\\\\\\\dashrightarrow{\pmb{\sf{x = 5}}}\end{gathered}⇢7x+10+5x+10=9x+7x⇢9x–5x=20⇢4x=20⇢x=420⇢x=5x=5</p><p></p><p>∴ Hence, present age of Sonal and Manoj is 35 and 25 years.</p><p></p><p>\rule{250px}{.2ex}</p><p></p><p>Let the number be n.</p><p></p><p>⅔ of a number is greater than ⅓ by 3.</p><p></p><p>\begin{gathered}\dashrightarrow\sf \dfrac{2}{3}n = \dfrac{1}{3}n + 3 \\\\\\\dashrightarrow\sf \dfrac{2}{3}n - \dfrac{1}{3}n = 3\\\\\\\dashrightarrow\sf \dfrac{n}{3} = 3\\\\\\\dashrightarrow{\pmb{\sf{n = 9}}}\end{gathered}⇢32n=31n+3⇢32n−31n=3⇢3n=3⇢n=9n=9</p><p></p><p>∴ Hence, the number is 9.</p><p></p><p>\rule{250px}{.2ex}</p><p></p><p>Let x be the cost of chair. Then, table's cost be (x + 75)</p><p></p><p>A/Q,</p><p></p><p>The cost of 3 table and 2 chair is Rs. 1850.</p><p></p><p>⇥ 3(x + 75) + 2x = 1850</p><p></p><p>⇥ 3x + 225 + 2x = 1850</p><p></p><p>⇥ 5x = 1850 – 225</p><p></p><p>⇥ 5x = 1625</p><p></p><p>⇥ x = 1625/5</p><p></p><p>⇥ x = 325</p><p></p><p>∴ Hence, the cost of chair is 325 rs and cost of table is 400 rs.</p><p></p><p>\rule{250px}{.2ex}</p><p></p><p>Let the number be n.</p><p></p><p>⇥ 4n = n + 45</p><p></p><p>⇥ 4n – n = 45</p><p></p><p>⇥ 3n = 45</p><p></p><p>⇥ n = 45/3</p><p></p><p>⇥ n = 15.</p><p></p><p>∴ Hence, the number is 15.</p><p></p><p>$